Just deleted my roof rails on my 2006 x5. Everything unbolts from the outside.
Once the rails and hardware is off, your left with 10 holes through the body. It takes 8- 11/16 plugs and 2- 5/8 plugs purchased from Lowes, paint to match, put a little silicone on them and pop them in the holes. wipe the excess silicone off and they look factory.
Extremely easy.